In this week’s Dispatches from The Secret Library, Dr Oliver Tearle explores the meaning and origins of a famous Shakespeare phrase
‘Hoist with one’s own petard’. The expression is well-known, and its meaning is fairly clear to most people: it describes someone who has been scuppered by their own schemes, someone who has come a-cropper because of some mischief they intended against others. But what is a ‘petard’, and where does it come from?